Raid storage-device-assisted read-modify-write system

ABSTRACT

A RAID storage-device-assisted RMW system includes a RAID primary data drive that retrieves second primary data via a DMA operation from a host system, and XOR&#39;s it with its first primary data to produce first interim parity data that it writes via a DMA operation to a RAID parity data drive. The RAID parity data drive XOR&#39;s its first parity data and the first interim parity data to produce second parity data that overwrites the first parity data. The RAID parity data drive also performs GF operations on the first interim parity data and its second interim parity data and XOR&#39;s the results to produce interim Q data that it writes via a DMA operation to a RAID Q data drive. The RAID Q data drive XOR&#39;s its first Q data and the interim Q data to produce second Q data that overwrites the first Q data.

BACKGROUND

The present disclosure relates generally to information handlingsystems, and more particularly to performing Read-Modify-Write (RMW)operations in an information handling system with the assistance of RAIDstorage devices.

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Information handling systems sometime utilize storage systems such asthose provided by a Redundant Array of Independent Disks (RAID) storagesystem that includes a plurality of RAID storage devices. As will beappreciated by one of skill in the art, RAID storage systems areprovided by a data storage virtualization technology that combines thephysical RAID storage devices into one or more logical storage units forthe purposes of data redundancy, performance improvements, and/or otherbenefits known in the art. For example, data in a RAID storage systemmay be distributed across the RAID storage devices using severaldifferent techniques that are referred to as “RAID levels” that providedifferent levels of redundancy and performance (e.g., RAID 0, RAID 1,RAID 5, RAID 6, and so on), with each RAID level providing a differentbalance among goals that include reliability, availability, performance,and capacity. However, the introduction of new storage technologies foruse in RAID storage systems has been found to raise some issues.

For example, Non-Volatile Memory express (NVMe) storage devices (e.g.,NVMe Solid State Drive (SSD) drives) utilize an open logical deviceinterface specification for accessing its non-volatile storage media(e.g., provided by NAND flash memory devices) via a Peripheral ComponentInterconnect express (PCIe) bus to provide low latency, internalparallelism, and/or other benefits known in the art. However, NVMestorage devices present a challenge when utilized with RAID storagesystems because the aggregate performance of the NVMe storage devices istypically much greater than the performance capabilities of the RAIDstorage controller provided for the RAID storage system (and thatperformance is even projected to be much greater than the performancecapabilities of next-generation RAID storage controllers), which resultsin those RAID storage controllers being unable to manage more than a fewNVMe storage devices (e.g., conventional RAID storage controllers arecurrently capable of managing approximately four NVMe storage devices).As such, the use of NVMe storage devices in RAID storage subsystemspresent RAID storage system scaling issues, as the RAID storagecontrollers cannot scale with more than a few NVMe storage devices. Suchscaling issues are particularly noticeable with regard toRead-Modify-Write (RMW) operations that used to generate parity data forstripes of data storage on the RAID storage system, which conventionallyinclude reading new primary data from a host system; reading old primarydata from a target RAID storage device that is to store the new primarydata; reading old parity data for the target stripe within which the newprimary data will be stored; calculating new parity data via an XORoperation using the new primary data, the old primary data, and the oldparity data; writing the new primary data to the target RAID storagedevice, and writing the new parity data for the target stripe.

Accordingly, it would be desirable to provide a RAID storage system thataddresses the issues discussed above.

SUMMARY

According to one embodiment, an Information Handling System (IHS)includes a first Redundant Array of Independent Disk (RAID) primary datastorage device that includes a first storage subsystem storing firstprimary data, wherein the first RAID primary data storage device isconfigured, in response to a first command received from a RAID storagecontroller device, to: retrieve, via a first Direct Memory Access (DMA)operation from a host system, second primary data; perform an XORoperation on the first primary data in the first storage subsystem andthe second primary data to produce first interim parity data; and write,via a second DMA operation to a second buffer subsystem in a RAID paritydata storage device, the first interim parity data; the RAID parity datastorage device that includes a second storage subsystem storing firstparity data and the second buffer subsystem storing the first interimparity data and second interim parity data, wherein the RAID parity datastorage device is configured, in response to a second command receivedfrom the RAID storage controller device, to: perform an XOR operation onthe first parity data in the second storage subsystem and the firstinterim parity data in the second buffer subsystem to produce secondparity data; and overwrite, in the second storage subsystem, the firstparity data with the second parity data; and wherein the RAID paritydata storage device is configured, in response to a third commandreceived from the RAID storage controller device, to: perform GaloisField (GF) operations on the first interim parity data and the secondinterim parity data in the second buffer subsystem to produce first GFinterim parity data and second GF interim parity data; perform an XORoperation on the first GF interim parity data and the second GF interimparity data to produce interim Q data; and write, via a third DMAoperation to a third buffer subsystem in a RAID Q data storage device,the interim Q data; and the RAID Q data storage device that includes athird storage subsystem storing first Q data and the third buffersubsystem storing the interim Q data, wherein the RAID Q data storagedevice is configured, in response to a fourth command received from theRAID storage controller device, to: perform an XOR operation on thefirst Q data in the third storage subsystem and the interim Q data inthe third buffer subsystem to produce second Q data; and overwrite, inthe third storage subsystem, the first Q data with the second Q data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an embodiment of an InformationHandling System (IHS).

FIG. 2 is a schematic view illustrating an embodiment of a RAID storagesystem.

FIG. 3 is a schematic view illustrating an embodiment of a RAID storagedevice that may be provided in the RAID storage system of FIG. 2.

FIG. 4A is a flow chart illustrating an embodiment of a portion of amethod for assisting with Read-Modify-Write (RMW) operations using RAIDstorage devices.

FIG. 4B is a flow chart illustrating an embodiment of a portion of amethod for assisting with Read-Modify-Write (RMW) operations using RAIDstorage devices.

FIG. 5 is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 6A is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 6B is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 6C is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 6D is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 6E is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 7A is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 7B is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 7C is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 8A is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 8B is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 8C is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 8D is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 9A is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 9B is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

FIG. 9C is a schematic view illustrating an embodiment of the RAIDstorage system of FIG. 2 operating during the method of FIGS. 4A and 4B.

DETAILED DESCRIPTION

For purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, calculate, determine, classify, process, transmit, receive,retrieve, originate, switch, store, display, communicate, manifest,detect, record, reproduce, handle, or utilize any form of information,intelligence, or data for business, scientific, control, or otherpurposes. For example, an information handling system may be a personalcomputer (e.g., desktop or laptop), tablet computer, mobile device(e.g., personal digital assistant (PDA) or smart phone), server (e.g.,blade server or rack server), a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include random accessmemory (RAM), one or more processing resources such as a centralprocessing unit (CPU) or hardware or software control logic, ROM, and/orother types of nonvolatile memory. Additional components of theinformation handling system may include one or more disk drives, one ormore network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse,touchscreen and/or a video display. The information handling system mayalso include one or more buses operable to transmit communicationsbetween the various hardware components.

In one embodiment, IHS 100, FIG. 1, includes a processor 102, which isconnected to a bus 104. Bus 104 serves as a connection between processor102 and other components of IHS 100. An input device 106 is coupled toprocessor 102 to provide input to processor 102. Examples of inputdevices may include keyboards, touchscreens, pointing devices such asmouses, trackballs, and trackpads, and/or a variety of other inputdevices known in the art. Programs and data are stored on a mass storagedevice 108, which is coupled to processor 102. Examples of mass storagedevices may include hard discs, optical disks, magneto-optical discs,solid-state storage devices, and/or a variety other mass storage devicesknown in the art. IHS 100 further includes a display 110, which iscoupled to processor 102 by a video controller 112. A system memory 114is coupled to processor 102 to provide the processor with fast storageto facilitate execution of computer programs by processor 102. Examplesof system memory may include random access memory (RAM) devices such asdynamic RAM (DRAM), synchronous DRAM (SDRAM), solid state memorydevices, and/or a variety of other memory devices known in the art. Inan embodiment, a chassis 116 houses some or all of the components of IHS100. It should be understood that other buses and intermediate circuitscan be deployed between the components described above and processor 102to facilitate interconnection between the components and the processor102.

Referring now to FIG. 2, an embodiment of a Redundant Array ofIndependent Disks (RAID) storage system 200 is illustrated. In theillustrated embodiment, the RAID storage system 200 includes a hostsystem 202. In an embodiment, the host system 202 may be provided by theIHS 100 discussed above with reference to FIG. 1, and/or may includesome or all of the components of the IHS 100. For example, the hostsystem 202 may include server device(s), desktop computing device(s), alaptop/notebook computing device(s), tablet computing device(s), mobilephone(s), and/or any other host devices that one of skill in the art inpossession of the present disclosure would recognize as operatingsimilarly to the host system 202 discussed below. In the illustratedembodiment, the RAID storage system 200 also includes a RAID storagecontroller system 204 that is coupled to the host system 202 and thatmay be provided by the IHS 100 discussed above with reference to FIG. 1,and/or may include some or all of the components of the IHS 100. Forexample, the RAID controller system 204 may include any storagedevice/disk array controller device that is configured to managephysical storage devices and present them to host systems as logicalunits.

Furthermore, the RAID storage system 200 also includes a plurality ofRAID storage devices that are illustrated in FIG. 2 as a plurality ofRAID primary data storage devices 206 a and up to 206 b, a RAID paritystorage data device 206 c, and a RAID Q data storage device 206 d, eachof which is coupled to the host system 202 and the RAID storagecontroller system 204. As will be appreciated by one of skill in the artin possession of the present disclosure, the RAID storage devices in theRAID storage system 200 of FIG. 2 are in a RAID 6 configuration, withthe RAID primary data storage devices 206 a and up to 206 b configuredto store primary data (e.g., provided by the host system 202), the RAIDparity data storage device 206 c configured to store parity data thatmay be utilized to recover primary data when that primary data becomesunavailable on one of the RAID primary data storage devices 206 a-206 b,and the RAID Q data storage device 206 c configured to store Q data thatmay be utilized to recover primary data and, in some cases, parity datawhen that primary/parity data becomes unavailable on any two of the RAIDprimary data storage device 206 a-206 b and the RAID parity data storagedevice 206 c.

However, while a few RAID storage devices in a particular configurationare illustrated, one of skill in the art in possession of the presentdisclosure will recognize that many more storage devices may (andtypically will) be coupled to the RAID storage controller system 204(e.g., in a datacenter) and may be provided in other RAID configurationswhile remaining within the scope of the present disclosure. In theembodiments discussed below, the RAID storage devices 206 a-206 d aredescribed as being provided by Non-Volatile Memory express (NVMe) SolidState Drive (SSD) drives, but one of skill in the art in possession ofthe present disclosure will recognize that other types of storagedevices with similar functionality as the NVMe SSD drives (e.g., NVMePCIe add-in cards, NVMe M.2 cards, etc.) may be implemented according tothe teachings of the present disclosure and thus will fall within itsscope as well. While a specific RAID storage system 200 has beenillustrated and described, one of skill in the art in possession of thepresent disclosure will recognize that the RAID storage system of thepresent disclosure may include a variety of components and componentconfigurations while remaining within the scope of the presentdisclosure as well.

Referring now to FIG. 3, an embodiment of a RAID storage device 300 isillustrated that may provide any or all of the RAID primary data storagedevices 206 a-206 b, the RAID parity data storage device 206 c, and/orthe RAID Q data storage device 206 d discussed above with reference toFIG. 2. As such, the RAID storage device 300 may be provided by an NVMeSSD storage device, but one of skill in the art in possession of thepresent disclosure will recognize that other types of storage deviceswith similar functionality as the NVMe SSD storage devices (e.g., NVMePCIe add-in cards, NVMe M.2 cards, etc.) may be provided according tothe teachings of the present disclosure and thus will fall within itsscope as well. In the illustrated embodiment, the RAID storage device300 includes a chassis 302 that houses the components of the RAIDstorage device 300, only some of which are illustrated below. Forexample, the chassis 302 may house a processing system (not illustrated,but which may include the processor 102 discussed above with referenceto FIG. 1) and a memory system (not illustrated, but which may includethe memory 114 discussed above with reference to FIG. 1) that is coupledto the processing system and that includes instructions that, whenexecuted by the processing system, cause the processing system toprovide a RAID storage engine 304 that is configured to perform thefunctionality of the RAID storage engines and/or RAID storage devicesdiscussed below. While not illustrated, one of skill in the art inpossession of the present disclosure will recognize that the RAIDstorage engine 304 may include, or be coupled to, other components suchas queues (e.g., the submission queues and completion queues discussedbelow) and/or RAID storage device components that would be apparent toone of skill in the art in possession of the present disclosure.

The chassis 302 may also house a storage subsystem 306 that is coupledto the RAID storage engine 304 (e.g., via a coupling between the storagesubsystem 306 and the processing system). Continuing with the exampleprovided above in which the RAID storage device 300 is an NVMe SSDstorage device, the storage subsystem 306 may be provided by a flashmemory array such as, for example, a plurality of NAND flash memorydevices. However, one of skill in the art in possession of the presentdisclosure will recognize that the storage subsystem 306 may be providedusing other storage technologies while remaining within the scope of thepresent disclosure as well. The chassis 302 may also house a buffersystem 308 that includes a first buffer subsystem 308 a that is coupledto the RAID storage engine 304 (e.g., via a coupling between the firstbuffer subsystem 308 a and the processing system), and a second buffersubsystem 308 b that is coupled to the RAID storage engine 304 (e.g.,via a coupling between the second buffer subsystem 308 b and theprocessing system). For example, the buffer system 308 may be providedby one or more buffer memory devices that include a first set of memoryaddress ranges that provide the first buffer subsystem 308 a, and asecond set of memory address ranges that provide the second buffersubsystem 308 b. Continuing with the example provided above in which theRAID storage device 300 is an NVMe SSD storage device, the first buffersubsystem 308 a may be provided by a portion of the buffer system 308that is often referred to as the “device buffer”. However, one of skillin the art in possession of the present disclosure will recognize thatthe first buffer subsystem 308 a may be provided using other buffertechnologies while remaining within the scope of the present disclosureas well.

Similarly, continuing with the example provided above in which the RAIDstorage device 300 is an NVMe SSD storage device, the second buffersubsystem 308 b may be provided by a portion of the buffer system 308that is often referred to as the “Controller Memory Buffer (CMB)”,“scratchpad buffer”, or “cache buffer”. In an embodiment, the secondbuffer subsystem 308 b/CMB may be provided by a subset of the buffersystem 308 that is distinguished from the first buffer subsystem 308a/device buffer. For example, the second set of memory address ranges inthe buffer memory device(s) that provide the second buffer subsystem 308b/CMB may be mapped to the PCIe memory space of the host system 202,which one of skill in the art in possession of the present disclosurewill recognize makes the second buffer subsystem 308 b/CMB visible tothe host system 202 while the rest of the buffer system 308 (e.g., thefirst buffer subsystem 308 a/device buffer) is not (i.e., due to thefirst set of memory address ranges in the buffer memory device(s) thatprovide the first buffer subsystem 308 a/device buffer not being mappingto the PCIe memory space of the host system 202.) As will be appreciatedby one of skill in the art in possession of the present disclosure,mapping the second buffer subsystem 308 b/CMB to the PCIe memory spaceof the host system 202 allows for the second buffer subsystem 308 b/CMBto be the target of the Direct Memory Access (DMA) data operationdiscussed below. However, one of skill in the art in possession of thepresent disclosure will recognize that the second buffer subsystem 308 bmay be provided using other buffer technologies while remaining withinthe scope of the present disclosure as well. The chassis 302 may alsohouse a storage system (not illustrated, but which may be provided bythe storage device 108 discussed above with reference to FIG. 1) that iscoupled to the RAID storage engine 304 (e.g., via a coupling between thestorage system and the processing system) and that includes a RAIDstorage database 309 that is configured to store any of the informationutilized by the RAID storage engine 304 as discussed below.

The chassis 302 may also house a communication system 310 that iscoupled to the RAID storage engine 304 (e.g., via a coupling between thecommunication system 310 and the processing system), the first buffersubsystem 308 a, and the second buffer subsystem 308 b, and that may beprovided by any of a variety of storage device communicationtechnologies and/or any other communication components that would beapparent to one of skill in the art in possession of the presentdisclosure. Continuing with the example provided above in which the RAIDstorage device 300 is an NVMe SSD storage device, the communicationsystem 310 may include any NVMe SSD storage device communicationcomponents that enable the Direct Memory Access (DMA) operationsdescribed below, the submission and completion queues discussed below,as well as any other components that provide NVMe SDD storage devicecommunication functionality that would be apparent to one of skill inthe art in possession of the present disclosure. While a specific RAIDstorage device 300 has been illustrated, one of skill in the art inpossession of the present disclosure will recognize that RAID storagedevices (or other devices operating according to the teachings of thepresent disclosure in a manner similar to that described below for theRAID storage device 300) may include a variety of components and/orcomponent configurations for providing conventional RAID storage devicefunctionality, as well as the functionality discussed below, whileremaining within the scope of the present disclosure as well.

Referring now to FIGS. 4A and 4B, an embodiment of a method 400 forassisting with Read-Modify-Write (RMW) operations using RAID storagedevices is illustrated. As discussed below, the systems and methods ofthe present disclosure provide for the performance of RMW operations tostore and backup data in a RAID storage system with the assistance ofthe RAID storage devices that store that data. For example, a RAIDprimary data storage device may receive a command from a RAID storagecontroller device and, in response, may retrieve second primary datafrom a host system via a first Direct Memory Access (DMA) operation,perform an XOR operation on first primary data in a first storagesubsystem in the first RAID primary data storage device and the secondprimary data to produce first interim parity data, and write the firstinterim parity data to a second buffer subsystem in a RAID parity datastorage device via a second DMA operation. The RAID parity data storagedevice may then receive a second command from the RAID storagecontroller device and, in response, may perform an XOR operation onfirst parity data in a second storage subsystem in the RAID parity datastorage device and the first interim parity data in the second buffersubsystem to produce second parity data, and overwrite the first paritydata with the second parity data in the second storage subsystem.

The RAID parity data storage device may then receive a third commandfrom the RAID storage controller device and, in response, may performGalois Field (GF) operations on the first interim parity data and secondinterim parity data in the second buffer subsystem to produce first GFinterim parity data and second GF interim parity data, perform an XORoperation on the first GF interim parity data and the second GF interimparity data to produce interim Q data, and write the interim Q data to athird buffer subsystem in a RAID Q data storage device. The RAID Q datastorage device may then receive a fourth command from the RAID storagecontroller device and, in response, may perform an XOR operation onfirst Q data in a third storage subsystem in the RAID Q data storagesystem and the interim Q data in the third buffer subsystem to producesecond Q data, and overwrite the first Q data with the second Q data inthe third storage subsystem. As such, RMW operations are offloaded fromthe RAID storage controller device, thus increasing the ability of theRAID storage controller device to scale with high performance RAIDstorage devices.

With reference to FIG. 5, the RAID storage system 200 is illustratedwith the RAID primary storage device 206 a storing primary data 500 a inits storage subsystem 306, and the RAID primary data storage device 206b storing primary data 500 b in its storage subsystem 306. While onlytwo RAID primary data storage devices are illustrated and described inthe examples provided below, one of skill in the art in possession ofthe present disclosure will recognize that any number of RAID primarydata storage devices may store primary data while remaining within thescope of the present disclosure as well. In addition, the RAID storagesystem 200 is also illustrated with the RAID parity data storage device206 c storing parity data 502 in its storage subsystem 306, and one ofskill in the art in possession of the present disclosure will recognizethat the parity data 502 may have been generated via an XOR operationperformed on the primary data 500 a-500 b in the RAID primary datastorage devices 206 a-206 b, and allows for the rebuilding of anyprimary data stored on any one RAID primary data storage device in theevent that primary data/RAID primary data storage device becomesunavailable.

Furthermore, the RAID storage system 200 is also illustrated with theRAID Q data storage device 206 c storing Q data 504 in its storagesubsystem 306, and one of skill in the art in possession of the presentdisclosure will recognize that the Q data 504 may have been generatedvia Galois Field (GF) and XOR operations performed on the primary data500 a-5006 in the RAID primary data storage devices 206 a-206 c, and theparity data 502 in the RAID parity data storage device 206 c, and allowsfor the rebuilding of any primary data, and in some cases parity data,stored on any two RAID storage devices (e.g., RAID primary data storagedevice(s) 206 a, 206 b and, in some cases, the RAID parity data storagedevice 206C) in the event that data/those RAID storage devices becomeunavailable. As will also be appreciated by one of skill in the art inpossession of the present disclosure, the primary/parity/Q data storageconfiguration illustrated in FIG. 5 provides primary/parity/Q data for asingle data strip, and different data strips may have differentprimary/parity/Q data storage configurations (e.g., in a plurality ofRAID storage devices provided in a RAID storage system, a first datastripe may include primary data on first and second RAID storage device,parity data on a third RAID storage device, and Q data on a fourth RAIDstorage device; a second data stripe may include primary data on thesecond and third RAID storage device, parity data on the fourth RAIDstorage device, and Q data on the first RAID storage device; a thirddata stripe may include primary data on the third and fourth RAIDstorage device, parity data on the first RAID storage device, and Q dataon the second RAID storage device, etc.) As such, while a particularRAID storage system device and data configuration is illustrated forpurposes of the examples below, one of skill in the art in possession ofthe present disclosure will recognize that a variety of device and dataconfigurations will fall within the scope of the present disclosure aswell.

The method 400 begins at block 402 where RAID primary data storagedevices receive a command from a RAID storage controller device. In anembodiment, at block 402, the RAID storage controller device 204 maygenerate and transmit a command to a RAID primary data storage device.With reference to FIG. 6A, the host system 202 may generate a writecommand 600 that instructs the writing of primary data that is locatedon the host system 200 to the RAID primary data storage devices 206a-206 b, and may transmit that write command 600 to the RAID storagecontroller device 204. As will be appreciated by one of skill in the artin possession of the present disclosure, the generation and/ortransmission of the write command 600 by the host system 202 to the RAIDstorage controller device 204 at block 402 may include a variety ofcontrol plane communications between the host system 202 and the RAIDstorage controller device 204 that have been omitted for clarity ofdiscussion. As such, at block 402, the RAID storage controller device204 may receive the write command 600 and, in response to that writecommand 600, may generate a command 602 and transmit the command 602 tothe RAID primary data storage device 206 b.

In some embodiments, the command 602 may be a multi-operation commandlike those described in U.S. patent application Ser. No. 16/585,296,attorney docket no. 16356.2084US01, filed on Sep. 27, 2019. For example,the command 602 may be an NVMe WRITE WITH XOR multi-operation commandthat is configured to cause the RAID primary data storage device 206 bto perform the multiple operations described below. However, whiledescribed as providing a multi-operation command at block 402, one ofskill in the art in possession of the present disclosure will recognizethat the multiple operations performed by the RAID primary data storagedevice 206 b discussed below may be performed in response to respectivecommands transmitted by the RAID storage controller device 204 whileremaining within the scope of the present disclosure as well. In aspecific example, the transmission of the command 602 may include theRAID storage controller device 204 providing the command 602 in asubmission queue that is included in the communication system 310 in theRAID primary data storage device 206 b/ 300, and then ringing a doorbellfor the RAID primary data storage device 206 b/ 300. However, one ofskill in the art in possession of the present disclosure will recognizethat the command 602 may be provided to the RAID primary data storagedevice 206 b in a variety of manners that will fall within the scope ofthe present disclosure as well.

As such, in some examples the RAID storage engine 304 in the RAIDprimary data storage device 206 b/ 300 may respond to the ringing of itsdoorbell by accessing the command 602 in the submission queue in itscommunication system 310. In embodiments in which the command 602 is amulti-operation command, the RAID storage engine 304 in the RAID primarydata storage device 206 b/ 300 may identify the multiple operationsinstructed by that command 602 (as described in U.S. patent applicationSer. No. 16/585,296, attorney docket no. 16356.2084US01, filed on Sep.27, 2019.) However, while a single RAID primary data storage device isillustrated and described below as receiving the command 602 that causesit to update its primary data 500 b, one of skill in the art inpossession of the present disclosure will recognize how multiple RAIDprimary storage devices may receive similar commands at block 402 whileremaining within the scope of the present disclosure as well.

The method 400 then proceeds to block 404 where the RAID primary datastorage devices retrieve primary data from a host system. With referenceto FIG. 6B, in an embodiment of block 404 and based on the command 602(which is a multi-operation command as described above in thisembodiment), the RAID storage engine 304 in the RAID primary datastorage device 206 b/ 300 may operate to perform a Direct Memory Access(DMA) operation 604 that accesses primary data 606 that is stored on thehost system 220 (e.g., in a memory system or storage system included onthe host system 202) and writes that primary data 606 to its firstbuffer subsystem 308 a (e.g., in a device buffer in the RAID primarydata storage device 206 b as described in the example above). As will beappreciated by one of skill in the art in possession of the presentdisclosure, the primary data 606 may be an update to the primary data500 b stored in the storage subsystem 306 in the RAID primary datastorage device 206 b, although other primary data writing scenarios willfall within the scope of the present disclosure as well.

The method 400 then proceeds to block 406 where the RAID primary datastorage devices perform XOR operations on primary data to produceinterim parity data, and write the interim parity data to a RAID paritydata storage device. With reference to FIG. 6C, in an embodiment ofblock 406 and based on the command 602 (which is a multi-operationcommand as described above in this embodiment), the RAID storage engine304 in the RAID primary data storage device 206 b/ 300 may operate toperform an XOR operation 608 using the primary data 500 b in its storagesubsystem 306 and the primary data 606 in its first buffer subsystem 308a in order to produce interim parity data 612, and then perform a DMAoperation 610 that writes that interim parity data 612 to the secondbuffer subsystem 308 b (e.g., a CMB) in the RAID parity data storagedevice 206 c.

Furthermore, FIG. 6C illustrates how the RAID parity data storage device206 c may store additional interim parity data 614 in its second buffersubsystem 308 b. For example, if a write (or WRITE WITH XORmulti-operation command) spans multiple RAID primary data storagedevices, each of those RAID primary data storage devices may providerespective interim parity data in a manner that is substantially similarto that described for the RAID primary data storage device 206 b above.In the examples below, the interim parity data 612 and 614 is utilizedduring the method 400, and one of skill in the art in possession of thepresent disclosure will recognize that such interim parity data may begenerated by any RAID primary data storage device that experiences anupdate to its primary data in a manner similar to that described abovefor the RAID primary data storage device 206 b. Further still, FIG. 6Dillustrates how the RAID storage engine 304 in the RAID parity datastorage device 206 c may perform an overwrite operation 616 to overwritethe primary data 500 b in its storage subsystem 306 with the primarydata 606 in its first buffer subsystem 308 a based on the command 602(which is a multi-operation command as described above in thisembodiment), thus updating that primary data stored by the RAID primarydata storage device 206 b. One of skill in the art in possession of thepresent disclosure will recognize how RAID primary data storage devicesexperiencing similar primary data updates may perform similar primarydata overwriting operations while remaining within the scope of thepresent disclosure as well.

With reference to FIG. 6E, following completion of the operationsassociated with the command 602 (e.g., multiple operations associatedwith a multi-operation command as discussed above, following eachoperation associated with respective commands, etc.) the RAID storageengine 304 in the RAID primary data storage device 206 b/ 300 maygenerate and transmit a completion message 618 to the RAID storagecontroller device 204. For example, the RAID storage engine 304 in theRAID primary data storage device 206 b/ 300 may generate the completionmessage 618 and provide that completion message in a completion queue inits communication system 310, and then generate an interrupt to the RAIDstorage controller device 204 that causes the RAID storage controllerdevice 204 to access that completion queue and retrieve the completionmessage. However, while a specific technique for transmitting thecompletion message is described, one of skill in the art in possessionof the present disclosure will recognize that completion messages may betransmitted using a variety of other techniques while remaining withinthe scope of the present disclosure. Furthermore, one of skill in theart in possession of the present disclosure will recognize that otherRAID primary data storage devices experiencing similar primary dataupdates (as discussed above) may transmit similar completion messages tothe RAID storage controller device 204 following their update operations(e.g., the multiple operations in the WRITE WITH XOR multi-operationcommand discussed above), and the RAID storage controller device 204 maywait to receive completion messages from each RAID primary data storagedevice experiencing an update prior to proceeding with the method 400.

The method 400 then proceeds to block 408 where the RAID parity datastorage device receives a command from the RAID storage controllerdevice. In an embodiment, at block 408, the RAID storage controllerdevice 204 may generate and transmit a command to a RAID parity datastorage device. For example, and as discussed above, the RAID storagecontroller device 204 may determine that completion messages from eachRAID primary data storage device experiencing an update have beenreceived as discussed above and, in response, at block 404 the RAIDstorage controller device 204 may generate a command 700 and transmitthe command 700 to the RAID parity data storage device 206 c.

Similarly as discussed above, the command 700 may be a multi-operationcommand like those described in U.S. patent application Ser. No.16/585,296, attorney docket no. 16356.2084US01, filed on Sep. 27, 2019.For example, the command 700 may be an NVMe WRITE PARITY multi-operationcommand that is configured to cause the RAID parity data storage device206 c to perform the multiple operations described below. However, whiledescribed as providing a multi-operation command at block 408, one ofskill in the art in possession of the present disclosure will recognizethat the multiple operations performed by the RAID parity data storagedevice 206 c discussed below may be performed in response to respectivecommands transmitted by the RAID storage controller device 204 whileremaining within the scope of the present disclosure as well. In aspecific example, the transmission of the command 700 may include theRAID storage controller device 204 providing the command 700 in asubmission queue that is included in the communication system 310 in theRAID parity data storage device 206 c/ 300, and then ringing a doorbellfor the RAID parity data storage device 206 c/ 300. However, one ofskill in the art in possession of the present disclosure will recognizethat the command 700 may be provided to the RAID parity data storagedevice 206 c in a variety of manners that will fall within the scope ofthe present disclosure as well.

As such, in some examples the RAID storage engine 304 in the RAID paritydata storage device 206 c/ 300 may respond to the ringing of itsdoorbell by accessing the command 700 in the submission queue in itscommunication system 310. In embodiments in which the command 700 is amulti-operation command, the RAID storage engine 304 in the RAID paritydata storage device 206 c/ 300 may identify the multiple operationsinstructed by that command 700 (as described in U.S. patent applicationSer. No. 16/585,296, attorney docket no. 16356.2084US01, filed on Sep.27, 2019.)

The method 400 then proceeds to block 410 where the RAID parity datastorage device performs an XOR operation on first parity data andinterim parity data to produce second parity data, and overwrites thefirst parity data with the second parity data. With reference to FIG.7B, in an embodiment of block 410 and based on the command 700 (which isa multi-operation command as described above in this embodiment), theRAID storage engine 304 in the RAID parity data storage device 206 c/300 may operate to perform an XOR operation 702 using the parity data502 in its storage subsystem 306 and the interim parity data 612 and 614in its second buffer subsystem 308 b (e.g., a CMB) in order to produceparity data 706, and then perform an overwrite operation 704 tooverwrite the parity data 502 with the parity data 706 in its storagesubsystem 306 (as illustrated by the replacement of parity data 502 fromFIG. 7B with parity data 606 in FIG. 7C.) As will be appreciated by oneof skill in the art in possession of the present disclosure, the XORoperation 702 performed using the interim parity data 612 and 614 storedin the second buffer subsystem 308 b may include any interim parity dataprovided by any RAID primary data storage device experiencing a primarydata update as discussed above.

With reference to FIG. 7C, following completion of the operationsassociated with the command 700 (e.g., multiple operations associatedwith a multi-operation command as discussed above, following eachoperation associated with respective commands, etc.) the RAID storageengine 304 in the RAID parity data storage device 206 c/ 300 maygenerate and transmit a completion message 708 to the RAID storagecontroller device 204. For example, the RAID storage engine 304 in theRAID parity data storage device 206 c/ 300 may generate the completionmessage 708 and provide that completion message in a completion queue inits communication system 310, and then generate an interrupt to the RAIDstorage controller device 204 that causes the RAID storage controllerdevice 204 to access that completion queue and retrieve the completionmessage. However, while a specific technique for transmitting thecompletion message is described, one of skill in the art in possessionof the present disclosure will recognize that completion messages may betransmitted using a variety of other techniques while remaining withinthe scope of the present disclosure.

The method 400 then proceeds to block 412 where the RAID parity datastorage device receives a command from the RAID storage controllerdevice. In an embodiment, at block 412, the RAID storage controllerdevice 204 may generate and transmit a command to a RAID parity datastorage device. For example, the RAID storage controller device 204 maydetermine that the completion message 708 was received from the RAIDparity data storage device 206 c as discussed above and, in response, atblock 412 the RAID storage controller device 204 may generate a command800 and transmit the command 800 to the RAID parity data storage device206 c.

Similarly as discussed above, the command 800 may be a multi-operationcommand like those described in U.S. patent application Ser. No.16/585,296, attorney docket no. 16356.2084US01, filed on Sep. 27, 2019.For example, the command 800 may be an NVMe GENERATE Q multi-operationcommand that is configured to cause the RAID parity data storage device206 c to perform the multiple operations described below. However, whiledescribed as providing a multi-operation command at block 412, one ofskill in the art in possession of the present disclosure will recognizethat the multiple operations performed by the RAID parity data storagedevice 206 c discussed below may be performed in response to respectivecommands transmitted by the RAID storage controller device 204 whileremaining within the scope of the present disclosure as well. In aspecific example, the transmission of the command 800 may include theRAID storage controller device 204 providing the command 800 in thesubmission queue that is included in the communication system 310 in theRAID parity data storage device 206 c/ 300, and then ringing a doorbellfor the RAID parity data storage device 206 c/ 300. However, one ofskill in the art in possession of the present disclosure will recognizethat the command 800 may be provided to the RAID parity data storagedevice 206 c in a variety of manners that will fall within the scope ofthe present disclosure as well.

As such, in some examples the RAID storage engine 304 in the RAID paritydata storage device 206 c/ 300 may respond to the ringing of itsdoorbell by accessing the command 800 in the submission queue in itscommunication system 310. In embodiments in which the command 800 is amulti-operation command, the RAID storage engine 304 in the RAID paritydata storage device 206 c/ 300 may identify the multiple operationsinstructed by that command 800 (as described in U.S. patent applicationSer. No. 16/585,296, attorney docket no. 16356.2084US01, filed on Sep.27, 2019.)

The method 400 then proceeds to block 414 where the RAID parity datastorage device performs Galois Field (GF) operations on interim paritydata to produce GF interim parity data. In some embodiments, the command800 may include an index into an inverse log table that provides for theretrieval of GF multiplicands. For example, the RAID storage engine 304in the RAID parity data storage device 206 c/ 300 may access an indexinto an inverse log table in the GENERATE Q multi-operation commanddiscussed above, and use that index to retrieve GF multiplicands (e.g.,gfLg, gfiLg, etc.) from a inverse log table (e.g., the GFF tables) thatis located in the RAID storage database 309 in the RAID parity datastorage device 206 c/ 300 for use in performing GF operations that oneof skill in the art in possession of the present disclosure wouldrecognize are commonly utilized with RAID 6 configurations. Thegeneration of such GF multiplicands and inverse log tables is outsidethe scope of the present disclosure, but one of skill in the art inpossession of the present disclosure will recognize how an inverse logtable with such GF multiplicands may be generated for the RAID storagesystem 200 while remaining within the scope of the present disclosure.Furthermore, while particular GF operations are illustrated anddescribed herein, one of skill in the art in possession of the presentdisclosure will recognize that other operations may be performed atblock 414 while remaining within the scope of the present disclosure aswell.

As such, with reference to FIGS. 8A and 8B and in an embodiment of block414, the RAID storage engine 304 in the RAID parity data storage device206 c/ 300 may utilize GF multiplicands retrieved using the command 800to perform GF operations on the interim parity data 612 in its secondbuffer subsystem 308 b to produce GFX interim parity data 612 a, andperform GF operations on the interim parity data 614 in its secondbuffer subsystem 308 b to produce GFX interim parity data 614 a. As willbe appreciated by one of skill in the art in possession of the presentdisclosure, the GF operation performed using the interim parity data 612and 614 stored in the second buffer subsystem 308 b may utilize anyinterim parity data provided by any RAID primary data storage deviceexperiencing a primary data update as discussed above. As such,following block 414, the second buffer subsystem 308 b in the RAIDparity data storage device 206 c may store the GFX interim parity data612 a and the GFX interim parity data 614 a produced via the GFoperations.

The method 400 then proceeds to block 416 where the RAID parity datastorage device performs an XOR operation on the GF interim parity datato produce interim Q data, and writes the interim Q data to a RAID Qdata storage device. With reference to FIG. 8C, in an embodiment ofblock 416 and based on the command 800 (which is a multi-operationcommand as described above in this embodiment), the RAID storage engine304 in the RAID parity data storage device 206 c/ 300 may operate toperform an XOR operation 802 using the GFX interim parity data 612 a andthe GFX interim parity data 614 a in its second buffer subsystem 308 bin order to produce interim Q data 806, and then perform a DMA operation804 that writes that interim Q data 806 to a second buffer subsystem 308b (e.g., a CMB) in the RAID Q data storage device 206 d.

With reference to FIG. 8D, following completion of the operationsassociated with the command 800 (e.g., multiple operations associatedwith a multi-operation command as discussed above, following eachoperation associated with respective commands, etc.) the RAID storageengine 304 in the RAID parity data storage device 206 c/ 300 maygenerate and transmit a completion message 808 to the RAID storagecontroller device 204. For example, the RAID storage engine 304 in theRAID parity data storage device 206 c/ 300 may generate the completionmessage 808 and provide that completion message in a completion queue inits communication system 310, and then generate an interrupt to the RAIDstorage controller device 204 that causes the RAID storage controllerdevice 204 to access that completion queue and retrieve the completionmessage. However, while a specific technique for transmitting thecompletion message is described, one of skill in the art in possessionof the present disclosure will recognize that completion messages may betransmitted using a variety of other techniques while remaining withinthe scope of the present disclosure. In an embodiment, following thetransmittal of the completion message 808 at block 414, the RAID storageengine 304 in the RAID parity data storage device 206 c/ 300 may clearinterim parity data (e.g., the interim parity data 612, the interimparity data 614, the GFX interim parity data 612 a, and/or the GFXinterim parity data 614 a) from its second buffer subsystem 308 b.

The method 400 then proceeds to block 418 where the RAID Q data storagereceives a command from the RAID storage controller device. In anembodiment, at block 418, the RAID storage controller device 204 maygenerate and transmit a command to a RAID Q data storage device. Forexample, the RAID storage controller device 204 may determine that thecompletion message 808 was received from the RAID parity data storagedevice 206 c as discussed above and, in response, at block 418 the RAIDstorage controller device 204 may generate a command 900 and transmitthe command 900 to the RAID Q data storage device 206 d.

Similarly as described above, the command 900 may be a multi-operationcommand like those described in U.S. patent application Ser. No.16/585,296, attorney docket no. 16356.2084US01, filed on Sep. 27, 2019.For example, the command 900 may be an NVMe WRITE Q multi-operationcommand that is configured to cause the RAID Q data storage device 206 dto perform the multiple operations described below. However, whiledescribed as providing a multi-operation command at block 418, one ofskill in the art in possession of the present disclosure will recognizethat the multiple operations performed by the RAID Q data storage device206 d discussed below may be performed in response to respectivecommands transmitted by the RAID storage controller device 204 whileremaining within the scope of the present disclosure as well. In aspecific example, the transmission of the command 900 may include theRAID storage controller device 204 providing the command 900 in thesubmission queue that is included in the communication system 310 in theRAID Q data storage device 206 d/ 300, and then ringing a doorbell forthe RAID Q data storage device 206 d/ 300. However, one of skill in theart in possession of the present disclosure will recognize that thecommand 900 may be provided to the RAID Q data storage device 206 d in avariety of manners that will fall within the scope of the presentdisclosure as well.

As such, in some examples the RAID storage engine 304 in the RAID Q datastorage device 206 d/ 300 may respond to the ringing of its doorbell byaccessing the command 900 in the submission queue in its communicationsystem 310. In embodiments in which the command 900 is a multi-operationcommand, the RAID storage engine 304 in the RAID Q data storage device206 d/ 300 may identify the multiple operations instructed by thatcommand 900 (as described in U.S. patent application Ser. No.16/585,296, attorney docket no. 16356.2084US01, filed on Sep. 27, 2019.)

The method 400 then proceeds to block 420 where the RAID Q data storagedevice performs an XOR operation on first Q data and the interim Q datato produce second Q data, and overwrites the first Q data with thesecond Q data. With reference to FIG. 9B, in an embodiment of block 420and based on the command 900 (which is a multi-operation command asdescribed above in this embodiment), the RAID storage engine 304 in theRAID Q data storage device 206 d/ 300 may operate to perform an XORoperation 902 using the Q data 504 in its storage subsystem 306 and theinterim Q data 806 in its second buffer subsystem 308 b (e.g., a CMB) inorder to produce Q data 906, and then perform an overwrite operation 904to overwrite the Q data 504 with the Q data 906 in its storage subsystem306 (as illustrated by the replacement of the Q data 504 from FIG. 9Bwith the Q data 906 in FIG. 9C.)

With reference to FIG. 9C, following completion of the operationsassociated with the command 900 (e.g., multiple operations associatedwith a multi-operation command as discussed above, following eachoperation associated with respective commands, etc.) the RAID storageengine 304 in the RAID Q data storage device 206 d/ 300 may generate andtransmit a completion message 908 to the RAID storage controller device204. For example, the RAID storage engine 304 in the RAID Q data storagedevice 206 d/ 300 may generate the completion message 908 and providethat completion message 908 in a completion queue in its communicationsystem 310, and then generate an interrupt to the RAID storagecontroller device 204 that causes the RAID storage controller device 204to access that completion queue and retrieve the completion message.However, while a specific technique for transmitting the completionmessage is described, one of skill in the art in possession of thepresent disclosure will recognize that completion messages may betransmitted using a variety of other techniques while remaining withinthe scope of the present disclosure. As also illustrated in FIG. 9C,following the receiving of the completion message 908, the RAID storagecontroller device 204 may generate and transmit a completion message 910to the host system 202 in order to indicate to the host system that thewrite command 600 has been completed.

Thus, systems and methods have been described that provide for theperformance of RMW operations to store and backup data in a RAID storagesystem with the assistance of the RAID storage devices that store thatdata. For example, one or more RAID primary data storage devices mayretrieve respective second primary data from a host system viarespective first DMA operations, perform respective XOR operations onrespective first primary data in their first storage subsystem and therespective second primary data to produce respective interim paritydata, and write the respective interim parity data to a second buffersubsystem in a RAID parity data storage device via a second DMAoperation. The RAID parity data storage device may then perform an XORoperation on first parity data in its second storage subsystem and therespective interim parity data in the second buffer subsystem to producesecond parity data, and overwrite the first parity data with the secondparity data in the second storage subsystem. The RAID parity datastorage device may then also perform GF operations on the respectiveinterim parity data in its second buffer subsystem to produce respectiveGF interim parity data, perform an XOR operation on the respective GFinterim parity data to produce interim Q data, and write the interim Qdata to a third buffer subsystem in a RAID Q data storage device. TheRAID Q data storage device may then perform an XOR operation on first Qdata in its third storage subsystem and the interim Q data in its thirdbuffer subsystem to produce second Q data, and overwrite the first Qdata with the second Q data in its third storage subsystem. As such, RMWoperations are offloaded from the RAID storage controller device, thusincreasing the ability of the RAID storage controller device to scalewith high performance RAID storage devices

Although illustrative embodiments have been shown and described, a widerange of modification, change and substitution is contemplated in theforegoing disclosure and in some instances, some features of theembodiments may be employed without a corresponding use of otherfeatures. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the scope of theembodiments disclosed herein.

1. A Redundant Array of Independent Disk (RAID) storage-device-assistedRead-Modify-Write (RMW) system, comprising: a host system; a RedundantArray of Independent Disk (RAID) storage controller device that iscoupled to the host system; and a plurality of RAID storage devices thatare each coupled to both the host system and the RAID storage controllerdevice, wherein the plurality of RAID storage devices include: a firstRAID primary data storage device that includes a first storage subsystemstoring first primary data, wherein the first RAID primary data storagedevice is configured, in response to a first command received from theRAID storage controller device, to: retrieve, via a first Direct MemoryAccess (DMA) operation from the host system, second primary data;perform an XOR operation on the first primary data in the first storagesubsystem and the second primary data to produce first interim paritydata; and write, via a second DMA operation to a second buffer subsystemin a RAID parity data storage device that is included in the pluralityof RAID storage devices, the first interim parity data; the RAID paritydata storage device that includes a second storage subsystem storingfirst parity data and the second buffer subsystem storing the firstinterim parity data and second interim parity data, wherein the RAIDparity data storage device is configured, in response to a secondcommand received from the RAID storage controller device, to: perform anXOR operation on the first parity data in the second storage subsystemand the first interim parity data in the second buffer subsystem toproduce second parity data; and overwrite, in the second storagesubsystem, the first parity data with the second parity data; andwherein the RAID parity data storage device is configured, in responseto a third command received from the RAID storage controller device, to:perform Galois Field (GF) operations on the first interim parity dataand the second interim parity data in the second buffer subsystem toproduce first GF interim parity data and second GF interim parity data;perform an XOR operation on the first GF interim parity data and thesecond GF interim parity data to produce interim Q data; and write, viaa third DMA operation to a third buffer subsystem in a RAID Q datastorage device that is included in the plurality of RAID storagedevices, the interim Q data; and the RAID Q data storage device thatincludes a third storage subsystem storing first Q data and the thirdbuffer subsystem storing the interim Q data, wherein the RAID Q datastorage device is configured, in response to a fourth command receivedfrom the RAID storage controller device, to: perform an XOR operation onthe first Q data in the third storage subsystem and the interim Q datain the third buffer subsystem to produce second Q data; and overwrite,in the third storage subsystem, the first Q data with the second Q data.2. The system of claim 1, wherein the plurality of RAID storage devicesinclude: a second RAID primary data storage device that includes afourth storage subsystem storing third primary data, wherein secondfirst RAID primary data storage device is configured, in response to afifth command received from the RAID storage controller device, to:retrieve, via a fourth DMA operation from the host system, fourthprimary data; perform an XOR operation on the third primary data in thefourth storage subsystem and the fourth primary data to produce thesecond interim parity data; and write, via a fifth DMA operation to thesecond buffer subsystem in the RAID parity data storage device, thesecond interim parity data.
 3. The system of claim 1, wherein the firstRAID primary data storage device is configured to: overwrite, in thefirst storage subsystem, the first primary data with the second primarydata.
 4. The system of claim 1, wherein the second buffer subsystem is aController Memory Buffer (CMB) included in the RAID parity data storagedevice, and the third buffer subsystem is a CMB included in the RAID Qdata storage device.
 5. The system of claim 1, wherein the first RAIDprimary data storage device is configured, in response writing the firstinterim parity data to the second buffer subsystem in the RAID paritydata storage device, to: provide a completion message to the RAIDstorage controller device, wherein the RAID storage controller device isconfigured to: provide the second command to the RAID parity datastorage device in response to receiving the completion message.
 6. Thesystem of claim 1, wherein the RAID parity data storage device isconfigured, in response overwriting the first parity data with thesecond parity data in the second storage subsystem, to: provide a firstcompletion message to the RAID storage controller device, wherein RAIDstorage controller device is configured to: provide the third command tothe RAID parity data storage device in response to receiving the firstcompletion message; and wherein the RAID parity data storage device isconfigured, in response to writing the interim Q data to the thirdbuffer subsystem in the RAID Q data storage device, to: provide a secondcompletion message to the RAID storage controller device, wherein theRAID storage controller device is configured to: provide the fourthcommand to the RAID Q data storage device in response to receiving thesecond completion message.
 7. An Information Handling System (IHS),comprising: a first Redundant Array of Independent Disk (RAID) primarydata storage device that includes a first storage subsystem storingfirst primary data, wherein the first RAID primary data storage deviceis configured, in response to a first command received from a RAIDstorage controller device, to: retrieve, via a first Direct MemoryAccess (DMA) operation from a host system, second primary data; performan XOR operation on the first primary data in the first storagesubsystem and the second primary data to produce first interim paritydata; and write, via a second DMA operation to a second buffer subsystemin a RAID parity data storage device, the first interim parity data; theRAID parity data storage device that includes a second storage subsystemstoring first parity data and the second buffer subsystem storing thefirst interim parity data and second interim parity data, wherein theRAID parity data storage device is configured, in response to a secondcommand received from the RAID storage controller device, to: perform anXOR operation on the first parity data in the second storage subsystemand the first interim parity data in the second buffer subsystem toproduce second parity data; and overwrite, in the second storagesubsystem, the first parity data with the second parity data; andwherein the RAID parity data storage device is configured, in responseto a third command received from the RAID storage controller device, to:perform Galois Field (GF) operations on the first interim parity dataand the second interim parity data in the second buffer subsystem toproduce first GF interim parity data and second GF interim parity data;perform an XOR operation on the first GF interim parity data and thesecond GF interim parity data to produce interim Q data; and write, viaa third DMA operation to a third buffer subsystem in a RAID Q datastorage device, the interim Q data; and the RAID Q data storage devicethat includes a third storage subsystem storing first Q data and thethird buffer subsystem storing the interim Q data, wherein the RAID Qdata storage device is configured, in response to a fourth commandreceived from the RAID storage controller device, to: perform an XORoperation on the first Q data in the third storage subsystem and theinterim Q data in the third buffer subsystem to produce second Q data;and overwrite, in the third storage subsystem, the first Q data with thesecond Q data.
 8. The IHS of claim 7, further comprising: a second RAIDprimary data storage device that includes a fourth storage subsystemstoring third primary data, wherein second first RAID primary datastorage device is configured, in response to a fifth command receivedfrom the RAID storage controller device, to: retrieve, via a fourth DMAoperation from the host system, fourth primary data; perform an XORoperation on the third primary data in the fourth storage subsystem andthe fourth primary data to produce the second interim parity data; andwrite, via a fifth DMA operation to the second buffer subsystem in theRAID parity data storage device, the second interim parity data.
 9. TheIHS of claim 7, wherein the first RAID primary data storage device isconfigured to: overwrite, in the first storage subsystem, the firstprimary data with the second primary data.
 10. The IHS of claim 7,wherein the second buffer subsystem is a Controller Memory Buffer (CMB)included in the RAID parity data storage device, and the third buffersubsystem is a CMB included in the RAID Q data storage device.
 11. TheIHS of claim 7, wherein the first RAID primary data storage device isconfigured, in response writing the first interim parity data to thesecond buffer subsystem in the RAID parity data storage device, to:provide a completion message to the RAID storage controller device,wherein the RAID storage controller device is configured to: provide thesecond command to the RAID parity data storage device in response toreceiving the completion message.
 12. The IHS of claim 7, wherein theRAID parity data storage device is configured, in response overwritingthe first parity data with the second parity data in the second storagesubsystem, to: provide a first completion message to the RAID storagecontroller device, wherein RAID storage controller device is configuredto: provide the third command to the RAID parity data storage device inresponse to receiving the first completion message.
 13. The IHS of claim12, wherein the RAID parity data storage device is configured, inresponse to writing the interim Q data to the third buffer subsystem inthe RAID Q data storage device, to: provide a second completion messageto the RAID storage controller device, wherein the RAID storagecontroller device is configured to: provide the fourth command to theRAID Q data storage device in response to receiving the secondcompletion message.
 14. A method for assisting with Read-Modify-Write(RMW) operations using Redundant Array of Independent Disk (RAID)storage devices, comprising: receiving, by a first Redundant Array ofIndependent Disk (RAID) primary data storage device from a RAID storagecontroller device, a first command and, in response: retrieving, by thefirst Redundant Array of Independent Disk (RAID) primary data storagedevice via a first Direct Memory Access (DMA) operation from a hostsystem, second primary data; performing, by the first RAID primary datastorage device, an XOR operation on first primary data in a firststorage subsystem in the first RAID primary data storage device and thesecond primary data to produce first interim parity data; and writing,by the first RAID primary data storage device via a second DMA operationto a second buffer subsystem in a RAID parity data storage device, thefirst interim parity data; receiving, by the RAID parity data storagedevice from the RAID storage controller device, a second command and, inresponse: performing, by the RAID parity data storage device, an XORoperation on first parity data in a second storage subsystem in the RAIDparity data storage device and the first interim parity data in thesecond buffer subsystem to produce second parity data; and overwriting,by the RAID parity data storage device in the second storage subsystem,the first parity data with the second parity data; receiving, by theRAID parity data storage device from the RAID storage controller device,a third command and, in response: performing, by the RAID parity datastorage device, Galois Field (GF) operations on the first interim paritydata and second interim parity data in the second buffer subsystem toproduce first GF interim parity data and second GF interim parity data;performing, by the RAID parity data storage device, an XOR operation onthe first GF interim parity data and the second GF interim parity datato produce interim Q data; and writing, by the RAID parity data storagedevice via a third DMA operation to a third buffer subsystem in a RAID Qdata storage device, the interim Q data; and receiving, by the RAID Qdata storage device from the RAID storage controller device, a fourthcommand and, in response: performing an XOR operation on first Q data ina third storage subsystem in the RAID Q data storage system and theinterim Q data in the third buffer subsystem to produce second Q data;and overwriting, by the RAID Q data storage device in the third storagesubsystem, the first Q data with the second Q data.
 15. The method ofclaim 14, further comprising: receiving, by a second RAID primary datastorage device from the RAID storage controller device, a fifth commandand, in response: retrieving, by the second RAID primary data storagedevice via a fourth DMA operation from a host system, third primarydata; performing, by the second RAID primary data storage device, an XORoperation on fourth primary data in a fourth storage subsystem in thesecond RAID primary data storage device and the third primary data toproduce the second interim parity data; and writing, by the second RAIDprimary data storage device via a fifth DMA operation to the secondbuffer subsystem in the RAID parity data storage device, the secondinterim parity data.
 16. The method of claim 14, further comprising:overwriting, by the first RAID primary data storage device in the firststorage subsystem, the first primary data with the second primary data.17. The method of claim 14, wherein the second buffer subsystem is aController Memory Buffer (CMB) included in the RAID parity data storagedevice, and the third buffer subsystem is a CMB included in the RAID Qdata storage device.
 18. The method of claim 14, further comprising:providing, by the first RAID primary data storage device in responsewriting the first interim parity data to the second buffer subsystem inthe RAID parity data storage device, a completion message to the RAIDstorage controller device; and providing, by the RAID storage controllerdevice in response to receiving the completion message, the secondcommand to the RAID parity data storage device.
 19. The method of claim14, further comprising: providing, by the RAID parity data storagedevice in response overwriting the first parity data with the secondparity data in the second storage subsystem a first completion messageto the RAID storage controller device; and providing, by the RAID paritydata storage device in response to receiving the first completionmessage, the third command to the RAID parity data storage device. 20.The method of claim 19, further comprising: providing, by the RAIDparity data storage device in response to writing the interim Q data tothe third buffer subsystem in the RAID Q data storage device, a secondcompletion message to the RAID storage controller device; and providing,by the RAID storage controller device, the fourth command to the RAID Qdata storage device in response to receiving the second completionmessage.